In the stepped-up Western sanctions on Iran – now at “unprecedented levels” – a significant and enabling development has been the agreement of Germany to participate in the pan-European embargo on Iranian oil after years of reluctance in Berlin to act so strongly against Tehran.

This German shift has finally produced a forceful common European front, in alignment with the U.S. and at odds with Russia and China, on imposing tough sanctions as a means short of war of convincing Iran to curb its nuclear program.

Chancellor Angela Merkel, like her partners in other EU capitals and in Washington, stresses that the economic pressure is designed to bring Iran to the point of making negotiated concessions that lessen suspicions that Tehran is secretly intent on building nuclear weapons.

The impact of the new embargo is unclear, especially since it has not been supported by Russia, or China and other major Asian importers of Iranian crude oil, as mentioned in a recent blog post by European Affairs. (Both Russia and China abstained from the UN vote on sanctions.)

But the demonstration of stronger transatlantic solidarity on Iran may help convince China, a key importer of Iranian oil, that the time has come to put more political pressure on Iran before some point-of-no-return is reached about implementing threats of a military attack as a last-ditch act to prevent Tehran from building nuclear weapons.

Both the British and the French governments have been pushing particularly hard for tough economic sanctions against Iran, especially since the UK’s embassy in Tehran was sacked earlier this year without any Iranian police intervention.

Now they have been joined by Germany, and it is a significant shift. The new German stance affords -- "a striking contrast with what was happening a year ago when Berlin was conspicuously less willing to step up to the issue," a U.S. policy-maker said in interview that could not be attributed to the person by name.